(Canto 15, line 30)
This is Brunetto Latini (1220-1294), politician, poet and scholar. A Guelf, he was quite influential in Florentine politics for some time. Though he was probably not Dante's teacher in a literal sense, Dante's immense respect for him is apparent in this passage. In 1260, he was sent as an envoy to Alfonso X of Castile, pleading for help against the Ghibellines, by this time allied with Manfred of Sicily. However, after the Guelf defeat at Montaperti and subsequent Ghibelline overtake of Florence, he was unable to return and was exiled in France until the Guelf victory at Benevento in 1266. After his return to Florence, he held various important positions, among them secretary to Guido di Monfort, Tuscan ambassador to the Sicilian king Charles I of Anjou. In 1273, he was appointed Secretary to the Council in Florence, and helped mediating the Guelf-Ghibelline conflict in 1280. In 1287, he finally became prior of Florence. He was noted for his learning and especially for his work "Li Livres dou Trésor", composed in French during his stay there. He also composed poetic works, among them the "Tesoretto" and the "Favoletto". The question of his "sodomy" is somewhat disputed, since it is not supported by any historical sources apart from the Comedy - this has led various commentators to suppose that his actual sin was contempt of his mother tongue (since he wrote in French), serving the city and not the monarchy, or even supporting a religious sect at the time; explanations which are perhaps not all that satisfying.